Abstract: Disclosed is a stamp for forming a tactile-detectable warning surface in moldable concrete or asphalt and method for employing same. The stamp consists of a mold member having truncated dome shaped indentations distributed therein in a warning pattern, each indentation optionally having an air hole located centrally therein, and, form rails distributed between indentations on the lower surface of the mold member and projecting downward there from, so as to force an even and consistent distribution of the moldable material into the indentations when the form rails are worked downward into the surface of the moldable material to form truncated domes. The stamp may further comprise one or more handles and upper rails distributed on the upper surface of the mold member.